1. Field of the Invention:
This invention relates to a pin-tucking device for folding a fabric in a pleated-like pattern at desired intervals in transverse relation to the direction of advance of the fabric at a stage prior to sewing by a sewing machine for sewing pin tucks.
2. Prior Art:
Generally, pin-tucking devices of this kind are so designed that a fabric is passed through a gap defined between a pair of guide plates, being thereby squeezed to have pleat-like folds formed thereon. If pleat-like folds are to be formed in a specified number and at given intervals, such device has a plurality of pairs of guide plates arranged in position.
One known type of such pin-tucking device has pairs of guide plates fixed integrally to upper and lower base plates by welding or otherwise. Another known type has such guide plates removably held in engagement with engagement grooves formed in upper and lower base plates.
The pin-tucking device of the former type has a difficulty that since it forms pleat-like folds on the fabric at uniform intervals, the guide plates have to be replaced together with the base plates if it is desired to change the intervals, and therefore that base plates having various different dimensions have to be prepared so as to meet needs for such change in intervals. As such, this known type is not economical. Furthermore, the fact that the guide plates are integral with the base plates requires that, if said intervals are to be changed without the base plates being replaced, sewing needles must be disposed correspondingly to the desired intervals of folds, instead of the intervals of folds formed by the pin-tucking device being changed, so that when tucks are actually formed on the fabric by sewing, some of the folds remain unstitched, it being thus necessary to carry out a post-stitching operation for removing such unstitched folds, in which respect the known type is far from being said to be of practical use.
The known pin-tucking device of the latter type, which has guide plates held in engagement with the engagement grooves in the base plates, has on one hand an advantage that the intervals of the pleat-like folds may be changed by suitably removing one of any particular pair of guide plates, but on the other hand it has a drawback that a multiplicity of engagement grooves of a particular configuration corresponding to that of guide plates must be formed in both of the base plates which are metal or synthetic resin made, which fact requires special machine tools and elaborate machining, thus involving high cost.
In aforesaid conventional devices, the upper base plate is made of transparent resin so as to facilitate early visual detection of any possible fabric lodging in the gap between a pair of guide plates while the fabric being passed through the gap, as well as of any irregularity present in the fabric, but the trouble is that such fabric lodging or fabric irregularity, if detected, cannot be removed unless the upper- and lower-base plate assembly is disassembled.